Mode truncation analysis in forced response of structural dynamics

Mode truncation in Modal analysis is an important problem and should be addressed with an effective truncation criterion. The truncation errors are considered as error forces and these error limits can be used to select the number of modes in the solution. Usually frequency based approach is used in selection of modes. But this method ignores the error forces in truncation and not effective if the cutoff frequency is greater than highest natural mode. An effective criterion would limit error forces, thereby minimizing errors in the response solution. To overcome the inaccuracies due to truncation, Mode Truncation Augmentation was used to represent the response due to non-retained modes due to its demonstrated superiority over other algorithms.;This work proposes a mode truncation criteria based on modal force contribution to estimate the number of modes required to approximate the response. The proposed algorithm is implemented with MTA. Several numerical examples were carried out to demonstrate the effectiveness of the proposed algorithm using MATLAB.